CVE-2024-38375: @fastly/js-compute use-after-free in some host call implementations

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-06-26 · updated 2026-06-17
Weakness: CWE-416

Description

@fastly/js-compute is a JavaScript SDK and runtime for building Fastly Compute applications. The implementation of several functions were determined to include a use-after-free bug. This bug could allow for unintended data loss if the result of the preceding functions were sent anywhere else, and often results in a guest trap causing services to return a 500. This bug has been fixed in version 3.16.0 of the `@fastly/js-compute` package.

Affected products

fastly js-compute-runtime: from 3.0.0, < 3.16.0

References

https://github.com/fastly/js-compute-runtime/commit/4e16641ef4e159c4a11b500ac861b8fa8d9ff5d3
https://github.com/fastly/js-compute-runtime/security/advisories/GHSA-mp3g-vpm9-9vqv
https://github.com/fastly/js-compute-runtime/commit/4e16641ef4e159c4a11b500ac861b8fa8d9ff5d3
https://github.com/fastly/js-compute-runtime/security/advisories/GHSA-mp3g-vpm9-9vqv

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